Merge pull request #76441 from vincentisambart/macro-decl-format

[SourceKit] Format macro decl without crashing

Author: ahoppen

lib/IDE/Formatting.cpp

@@ -1414,6 +1414,12 @@ class FormatWalker : public ASTWalker {
       // interpolated string literal.
       if (E->getArgs() == Args)
         ContextLoc = getContextLocForArgs(SM, E);
+    } else if (auto *D = Parent.getAsDecl()) {
+      if (auto *MED = dyn_cast<MacroExpansionDecl>(D)) {
+        if (MED->getArgs() == Args) {
+          ContextLoc = MED->getStartLoc();
+        }
+      }
     }
 
     auto Action = HandlePre(Args, Args->isImplicit());
@@ -2700,10 +2706,17 @@ class FormatWalker : public ASTWalker {
     if (TrailingTarget)
       return std::nullopt;
 
-    auto *ParentE = Parent.getAsExpr();
-    assert(ParentE && "Trailing closures can only occur in expr contexts");
-    return IndentContext{
-        ContextLoc, !OutdentChecker::hasOutdent(SM, ContextToEnd, ParentE)};
+    bool hasOutdent;
+    if (auto *ParentE = Parent.getAsExpr()) {
+      hasOutdent = OutdentChecker::hasOutdent(SM, ContextToEnd, ParentE);
+    } else if (auto *ParentD = Parent.getAsDecl()) {
+      assert(isa<MacroExpansionDecl>(ParentD) && "Trailing closures in decls can only occur in macro expansions");
+      hasOutdent = OutdentChecker::hasOutdent(SM, ContextToEnd, ParentD);
+    } else {
+      assert(false && "Trailing closures can only occur in expr contexts and macro expansions");
+      return std::nullopt;
+    }
+    return IndentContext{ContextLoc, !hasOutdent};
   }
 
   std::optional<IndentContext>

test/SourceKit/CodeFormat/indent-available-macro.swift

@@ -0,0 +1,9 @@
+@available(iOS 17, *)
+#Preview("") {
+UIView()
+}
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s >%t.response
+// RUN: %FileCheck --strict-whitespace %s <%t.response
+
+// CHECK: key.sourcetext: "    UIView()"